Izenour, George C., author
Yale University Press, 1996
Buku Teks
Izenour, George C., author
McGraw-Hill, 1977
Buku Teks
Vogt, William
New York, N.Y. WilliamSloane 1948,
Buku Teks
Chesler, Mark A.
Macmillan, 1981
Buku Teks
Kephart, William M.
St. Martin?s Press, 1976
Buku Teks